PSA would love to sell you a full rifle kit for $500. You can get a lower for about $130 after background and transfer fees.
Curt's on the Eastside would also love to sell you one of his very nice basic builds for about that much.
I hope I am not coming off like a dick here, I am honestly trying to be helpful. Is this helpful to the conversation? Not sure. Anyway, tough time to sell an AR if you are looking for top dollar.
you can pick up lowers for 100 with background check